Air cleaner



Oct. 20, 1942. R, MARSHALL? JR 2,299,332

AIR CLEANER Filed March 2, 1940' INVENTOR Patented a. 2o,"1942 UNITED; STATES PAT-VENT oFFlca Anfssassz a at." mm,

In, Portland, o

Application March 2, 1m, Serial No. 321,880

40mins.

My invention relates to improvements in dry centrifugal air cleaners for cleaning the air entering the cylinders of internal combustion en gines, in combination with an improved struc-.

ture for extracting entrained abrasive dust from the air, before it enters the engine or the carburetor as the case m y be.

An object of the invention is to so protect the engine induction pipe that a' minimum of abraslve dust will find opportunity to enter it. in any range of operation from lowest to highest speed.

'. Another object is to separat the dust segregated by influence of centrifugal force into a receptacle wherein it falls by gravity uninfluenced by the turbulence inseparable from centrifugal separation of dust from air.

Other objects that will be apparent from the following description of a preferred form vof the invention will be obvious to those to whom this specification is addressed; and are particularly pointed out in the claims which follow the description. v

It is not believed that the invention has any particular merit save in cases where air is induced into a separator, such as by suction influence of an internal combustion engine or a suction fan, and in the case of an engine it will operate far better on a multi-cylinder engine that induces practically a steady stream of incoming air-for combustion use. as distinguished from a single cylinder engine, particularly of the hitand-miss" governed type where the induction is interrupted.

A drawing of the preferred form of the invention is hereinafter described in detail by way of disclosure but this description is not intended as a limitation, the scope of the invention being intended to be ascertained from claim language.

In the drawing:

Fig. 1 is a view of the in this case the top:

Fig. 2 is a side elevation of the cleaner, with a part broken' away to show internal construction inlet end of the cleaner,

of an essential part that will later be described. in detail audits peculiar purpose explained: and

Fig. 3 is a section taken on line 3-3 of Fig. 2. A generally frusto-conical body If, is closed at its larger end by the head ll. save that an annular air intake portion is provided by the annular row of vanes 2|. These vanes 2I will be of selected pitch to impart a whirling motion to air entering therethrough. I An induction pipe II is made rigid with, the smaller and of the frusto-conical bo y I I. its axis air does not impinge directly against this open I I s end Ila.

. The smaller end of the frusto-conical body II is preferably made cylindrical as at I2, for a short distance, then'the walls are brought in abruptly to contact relationshipwith th outside of the induction pipe II, to which they are made fast by welding, brazing or other preferred method.

It will be understood that the word "frustoconical as applied to the element I'I refers to the inside surface and the outside surface is not intended to be defined. u

The induction pipe I: will have its outside and I3b in operative connection to a source of suction such as the intake of an internal combustion engine and it will be seen atonce that when such source is operating, air will enter the annular air intake, between the'vanes 2|, which by reason of theirshape will impart a whirling motion to the incoming air'that is proportional to its velocity of entrance.

It will also be seen that any entrained abrasive dust in suspension in this air will be thrown to the outside of the whirling conical mass of entering air because the unit specific gravity of such material is much greater than air. This principle of separating air from entrained mineral dust has often been proposed and I make no claim to structures employing it, broadly. However. it will now be seen that the induction pipe is so disposed with respect to its entrance Ila 85 that entering dust particles are prevented from entering it by virtue of the solid shield portion of the head II, which I believe to be new and know to be very important.

As the whirling body of air continues toenter 40 under influence of suction, the exceedingly thin wall of mineral dust that it contains continues to follow the inside surface of the body II under influence of maintained centrifugal force, finally reaching the cylindrical portion I2. of the body 45 II, with its tendency to fly still further practical- 1y undiminished; hence in whirling around the wall of this cylindrical portion II, it encounters theopening I4, which it enters. The conduit i is made rigid with and in sealed relationship to 50 the'body portion l2 and terminates in an abrupt turn or elbow iia, the conduit being hermetically being coincident with the axis of the body II and thread on the recep e Wh Will usually separator depends upon the fact that dust of abrasive character is always of mineral origin and heavier than air, though it may be in such small particles that it can be held in suspension in air for a considerable time. When such particles have centrifugal force applied to them by whirling a mass of air within which they are suspended, they tend to fly 01! at a tangent to the they can fly into a dead air space that is protected from turbulence reaching into it from the whirb ing air, they can and will settle into a pile.

I have discovered that means for inducing air by suction into a body, in the general form of a cone of whirling air, will rapidly place the heavy particles of abrasive dust at the perimeter of the,

cone, then the clean air can be drawn from the center of the base of the cone, which will be much cleaner than by any other structure with which I am familiar. But there is still another problem, that of taking care of the dust thrown outwardly, and depositing it within a turbulence i'ree receptacle. This is almost completely solved by connecting a dust conduitin communication with the perimeter of theicone, near its small end, the axis of which is substantially normal to theaxis oi' the cone. The length of the dust conduit is important and the longer it is the greater the effectiveness, up to say as much as four inches though I have not tested-one longer, since ordinarily there will not be room under an engine hood to accommodate a dust conduit that long with a receptacle on the end of it. I have found that putting a turn at'the end of the dust conduit is as eifective as several inches of dust conduit, the purpose of both being,'of course, to quiet any tendency to turbulence within the receptacle itself. I f

In Fig. 3, it is clearly shown that the end of the dust conduit l5, sealed over 'i theiopening'il, is considerably larger than the opening l4. Such construction is very importantiin killing turbulence, as ascertained by test. I therefore conclude that theelbow is an effective substitute for a long conduit and that the complete sealing of the receptacle is necessary to its successful operation as described; that the lead-oi! dust conduit must be generally normal to the axis of the cone and that initial separation of entrained dust from the air is best performed by the structure which naturally and normally keeps the induced air inthe shape of a hollow whirling cone, the induction pipe being inside the air body and it means are provided through which cone and located as near its hollow base as possiole, thus furthest from the dust.

it will be observed that this cleaner can be operated in a vertical or horizontal position by merely altering the manner of attaching container it.

I claim:

1. In an air cleaner, a body member containing a generally frust'o-conic'al chamber, a, base member for said chamber with a solid center and an annular vaned inlet, an induction pipe axially positioned insaid chamber in such manner that its inner end is shielded by the solid center of the base, and a dust tube normal to the smaller end of the chamber and in communication therewith, the said dust tube embodying a turn portion spaced from the chamber by the tube and a dust receptacle hermetically sealed to the outlet of the said turn portion. 7

2. In an air cleaner of the character described, a body member embodying a generally frustoconical chamber, an induction tube extending axially into said chamber through the smaller end to a point near the larger end, a shield moutlet of the turn portion in such position that it is adapted. to receive dust therefrom by gravity.

3. An air cleaner of the centrifugal separation type, comprising a frusto-conical chamber, a base member fitted to the larger end of said chamber, an annular system of vanes disposed around the perimeter of said base, a solid center in said base, an induction pipe extending into the chamber from the small end to a point short of the center of the base, a lateral dust outlet near the small end of the chamber, a dust conduit sealed over saidoutlet and a dust receptacle connected to said dust conduit.

4. A centrifugal air cleaner for an internal combustion engine, comprising a straight tubular member adapted for. engagement with the' 

